Just read an article about the Army wanting to get to a Brigade Combat Team (BCT) being able to sustain itself for a week of combat operations before needing resupply. As a retired Army loggie, I've seen this desire/"initiative" before. A few times. Never worked out once the Army got the price tag in terms of manpower, equipment, deployability, mobility, etc. It is always a wonderful idea until one gets down to the basics. Were it just sitting there in a static defense, maybe. But that is not the operational concept. Back in the '80s, it was the "Air/Land Battle Study" (derisively referred to as "AL(L)BS") by some in which a Corps (a number of Divisions - each with three-four brigades "punching through the front lines and operating independently for a week or so deep into enemy lines - creating havoc in the rear areas", then when the Army went to (or tried) to go Brigade-Centric - but don't call them Brigades or Divisions or Corps - call them "Units of Action (UA)", "Units of Employment (UEx and UEy)", and other nonsense. The whole idea was to get away from the standard mind-think of Brigades and Divisions and Corps by calling them something different. Fortunately, that concept went down in flames but we are in the Brigade Combat Team mode now - not much different, actually, than what a Regimental Combat Team was in WW-II. The Circle of Life...old enough to be considered "new".
The more variety you have in terms of parts, batteries, ammo, fuel, etc., the bigger challenge it is to try and anticipate - for a weeks' worth of combat - how much of each item one needs, with a healthy overage for the unexpected, since it is generally considered bad form to run out of ammo (or fuel) in the middle of a firefight...The Army "models" anticipated consumption of things like fuel and ammo and tires and track-pads for various combat operations, but just like Climate-Change modeling, it has challenges. Would you want to go into combat based on some model's computations that you'll only shoot 200 rounds per day from your M4, so a BCT will only have at hand 1,400 rounds per M4 before going into combat...How about other ammo? Fuzes for mortars and artillery, differing types of tank ammo, etc.
It was a PITA to transition to a common fuel.
Again, not to knock the 6.8, but everybody doesn't get to the same level of "modernization" overnight, and that means different parts and ammo during the "transition". As recently as 1995, there were still Reserve Component (National Guard and Army Reserve) that still had M1911s. Granted, they were at the bottom of the food chain, but it took well over a decade to transition fully to the M9. Switching to 6.8 will take well over a decade, and it will be painful for loggies. Might be a good thing - as long as we don't have a war in the mean time...
To be sure, the Army is trying to do modernization of entire Brigade Combat Teams at a time. It isn't easy, as one can imagine, and upgrading to 6.8 will be just one of many "upgrades" during a transition time. That means a BCT not available until the transition is complete, training is certified, and various stockage level of parts updated.
